What does brain CT mean by large occipital cistern?

Brain CT cisterna magna refers to cisterna magna in cerebellar cortex or cerebellar vermis more than 10mm away from occipital inner plate, generally on head CT can show similar cerebrospinal fluid density, location can be inferior cerebellum, posterior cerebellum, cerebellum, or connected into a whole, can communicate with superior cerebellar cisterna, lateral can reach occipital cerebellar angle cisterna. Generally, cisterna magna can be found in any age, size varies, the fourth ventricle is normal, there is no mass effect, hydrocephalus, occipital compression thinning, posterior cranial fossa size can be normal, there is no atrophy of the cerebellar vermis. Generally, there are no clinical symptoms, most of them are accidentally found on head CT, which is generally considered to be congenital anatomical variation and does not need treatment.